JPH018082Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of the lower link of a three-point linkage mechanism for mounting a working machine on a tractor.

For example, as shown in FIG. 3, the lower link 12 of a three-point linkage mechanism, which attaches a working machine such as a rotary furrow machine to an agricultural tractor so that it can be raised, lowered, and towed, has a base 14 pivoted on the tractor body 1, and is used for work. A tip portion 16 is pivotally connected to the machine 11, and a long straight midway portion 18 is formed from the base portion 14 to the tip end 16, and a lift rod 21 of the hydraulic device 3 is pivotally connected to the midway portion 18. ing.

The base portion 14 and the tip portion 16 are bent with respect to the midway portion 18, but this is due to the fact that the respective pivot pins 1
5 and 17, and since the center line α of the midway portion 18 is greatly inclined with respect to the center line β of the tractor body, the attachment portion 22 of the lift rod 21 is connected in a twisted state. If the lift rod 21 is in the lower position, it may be difficult to move up and down by the lift rod 21, and the lower link may not operate smoothly. In particular, in the case where a hydraulic cylinder 24 is provided on one side of the lift rod 21 to automatically horizontally control the rotary, smooth lifting and lowering of the lower link 12 is an essential requirement, and twisting of the lift rod 21 is a fatal defect. Become.

In addition, in agricultural tractors, a safety cover 5 is placed around the PTO shaft 4 to ensure the safety of the operator and protect the joint with the universal joint. The space between the lower link 12 and the cover 5 is narrow, so that when the lower link 12 swings left and right, it hits the safety cover 5, and it is difficult to connect the universal joint. This is remarkable in small-sized tractors where the distance between the left and right lower links 12 is narrow.

Therefore, a lower link shown in FIG. 4 can be considered as a lower link that reduces the twisting of the lift rod 21 with the mounting portion 22 and increases the distance between the lift rod 21 and the safety cover 5. This lower link 12 is bent so that the vicinity of the base 14 protrudes inwardly with respect to the centerline β of the tractor body 1, so that the midway portion 18 is separated outwardly from the safety cover and The inclination angle of α becomes smaller, and the lift rod 2
Complications with 1 will also be extremely reduced.

However, when such a lower link 12 swings from side to side, the middle part 18 may come into contact with the rear wheel 6, and the attachment part 2 of the lift rod 21 may come into contact with the rear wheel 6.
2 is largely deviated outward from the center line γ connecting the base 14 and the tip 16, so the lower link 12 is twisted when going up and down, making it difficult to go up and down.
It may cause damage.

In view of these various problems, the present invention is designed to increase the distance between the safety cover and the safety cover by bending the base so that the base protrudes inward and the tip protrudes outward from the center line of the tractor body. In addition, contact with the rear wheel can be avoided, and there is less twisting of the lift rod attachment part, and since it does not deviate much from the center line connecting the base and tip, there is less twisting of the lower link, allowing for smooth lifting and lowering. I made it possible3
The purpose is to provide a lower link of a point linkage mechanism.

To achieve this purpose, the present invention is characterized by a lower three-point link mechanism in which the base is pivoted to the tractor body, the tip is pivoted to the work machine, and the lift rod is connected to the middle part. In the link, the base of the lower link is bent inward and the tip thereof is bent outward with respect to the centerline of the tractor body, and the inclination angle of the centerline in the middle is such that the angle of inclination between the base and the tip is It is located at a point that is set smaller than the inclination angle of the connecting center line.

Embodiments of the present invention will be described below with reference to the drawings.

In Figures 1 and 2, reference numeral 1 denotes a tractor body composed of a transmission case, etc., which has a rear axle case 2 that protrudes from side to side, and a hydraulic system 3 for lifting and lowering the work machine is mounted on the upper part of the rear axle case 2. ing. 4 is a PTO shaft protruding from the rear of the tractor body 1;
A safety cover 5, which is also attached to the fuselage 1, covers the left and right sides and the top surface, and 6 is the rear wheel, and 7 is the rear wheel.
indicates a fuenda.

Reference numeral 10 denotes a three-point linkage mechanism for towing and attaching the work implement 11 to the tractor body 1, and is composed of a pair of left and right lower links 12, a check chain 13, a top link (not shown), and the like.

Each lower link 12 has a base 14 connected to the tractor body 1.
It is pivotally supported by a pin 15 provided at the rear lower part, and the tip part 1
6 is pivotally connected to a pin 17 of a working machine 11, and both parts 14 and 16 have a ball joint structure to allow relative inclination. A check chain 13 is stretched between the midway portion 18 and the rear axle case 2, and the lower link 12
This controls large lateral swings.

The lower link 12 has bent portions A, B, C, and D formed at four locations in the longitudinal direction. Bending part A,
D is a conventionally formed pin 15,
17, so that it is fitted and connected in a state perpendicular to 17, so that there is little twisting even when it shakes sideways.

The bent parts B and C are bent in opposite directions, and the part between them is the middle part 18, and the middle part 1
8, the base 14 side from the bent portion B protrudes inward near the center line β of the tractor body 1,
The tip portion 16 side from the bent portion B protrudes outward far from the center line β, and as the base portion 14 protrudes inward, the distance from the safety cover 5 increases, and the tip portion 16 protrudes outward. As a result, the distance from the rear wheel 6 is increased. Note that the bent portion C is located approximately at the same position as the outer periphery of the rear wheel 6.

Further, as is clear from FIG. 1, the inclination angle θ 1 of the center line α of the midway portion 18 with respect to the center line β of the tractor body 1 is the angle of inclination θ ₁ of the center line α connecting the base portion 14 and the tip portion 16 with respect to the center line It is sufficiently smaller than the inclination angle θ ₂ . A mounting portion 22 at the lower end of a lift rod 21 connected to a lift arm 20 of the hydraulic device 3 is connected with a pin to approximately the center of this midway portion 18, and this mounting portion 22 is formed into a bifurcated shape with a groove 23. Although the groove 23 is originally substantially in the front-back direction, it is slightly twisted in order to fit into the midway portion 18. To obtain this state,
The upper end of the lift rod 21 and the lift arm 20 are connected with a play or through a ball joint.
Since the inclination angle θ ₁ of the center line α is sufficiently small, twisting of the lift rod 21 is small, and relative rotation at each connecting portion between the lift arm 20 and the lower link 12 can be made extremely smoothly.

Since the lower link 12 is bent in opposite directions at the front and back, the center line γ passes through the approximately midway portion 18, and therefore the mounting portion 22 is approximately on the center line γ. No twisting torque is generated, and damage caused by the formation of the bent portion B is eliminated.

A hydraulic cylinder 24 is provided in the middle of the right side of the pair of left and right lift rods 21, and its length can be adjusted by supplying pressure oil from the tractor. The control valve that operates this hydraulic cylinder 24 is automatically controlled by a horizontal detection sensor attached to the work equipment 11, so that even if the tractor tilts due to unevenness in the field, the length of one lift rod 21 can be maintained. It is configured to automatically maintain the working machine 11 substantially horizontally by adjusting it.

As shown in FIG. 2, the safety cover 5 has a downward protrusion 25 formed at its lower part. If the lower link 12, especially the conventional lower link, is lowered to the lowest position and shakes sideways, the pin may come in from the bottom end of the safety cover 5 to below the PTO shaft 4. By forming the downward protrusion 25 that protrudes downward from the lower link 15, the lateral vibration of the lower link 12 is restricted and the PTO
It can be prevented from hitting the shaft 4 or the universal joint. This downward protrusion 25 is particularly advantageous when a conventional straight lower link 12 is used.

Note that since there is no protrusion at the lower part of the free end side of the safety cover 5, there is no problem in connecting the universal joint to the PTO shaft.

According to the present invention detailed above, the lower link 12
is bent so that its base 14 protrudes inwardly and its distal end 16 protrudes outward, and as a result, the center line α of the midway portion 18 is bent from the center line γ connecting the base 14 and distal end 16. Also, since the inclination angle θ with respect to the center line β of the tractor body 1 is set small, the distance between the safety cover 5 and the rear wheel 6 of the PTO shaft 4 can be increased, and the intermediate portion 18
The lift rod 21 connected to the
Compared to a structure in which only the lift rod 21 is bent, the mounting portion 22 of the lift rod 21 is located closer to the center line γ, so that the lower link 12 is less likely to twist and has sufficient durability.

[Brief explanation of the drawing]

Figures 1 and 2 are a plan view and a cross-sectional side view of the main parts, respectively, showing an embodiment of the present invention, Figure 3 is a plan view of a conventional example, and Figure 4 shows only the base of the lower link bent. FIG. 3 is a plan view showing an example. 1... Tractor body 1, 10... Three-point link mechanism, 11... Working machine, 12... Lower link, 14
...Base, 16...Tip, 18...Middle part, 2
1... Lift rod, α, β, γ... Center line,
θ ₁ , θ ₂ ...Inclination angle.

Claims (1)

[Scope of utility model registration request] In the lower link of a three-point linkage mechanism in which the base 14 is pivoted to the tractor body 1, the tip 16 is pivoted to the work implement 11, and the lift rod 21 is connected to the midway part 18, the center line β of the tractor body 1
On the other hand, the base 14 of the lower link is bent inward and the tip 16 is bent outward, and the inclination angle θ ₁ of the center line α of the midway portion 18 is the same as that of the base 14.
A lower link of a three-point linkage mechanism, characterized in that the inclination angle θ ₂ of the center line γ connecting the and the tip 16 is set smaller than the inclination angle θ 2 .